Narrow high powered signals may be transmitted periodically from a base station transmitter to allow a mobile device to identify a nearby transmitter and make various signal measurements. The signal measurements may be used to determine the relative strength of signals received from different transmitters and/or to make mobile adjustments, e.g., timing adjustments to facilitate communication with a base station from which a beacon signal is received.
In some systems beacon signals are transmitted periodically by each transmitter in a system. Normally neighboring transmitters transmit beacon signals at different times. In most cases wireless terminal receiving a beacon can identify the transmitter, e.g., base station or sector of a base station, from the frequency, time and/or other beacon signal related information. In some known systems beacon signals are transmitted using a single tone during a single symbol transmission period with data being transmitted by the transmitter in the following symbol period.
The narrowband nature of such beacon signals makes them difficult to use for timing synchronization. To facilitate timing synchronization, wideband signals from the transmitter would be preferable.
Given that beacon signals tend to be very high power signals they are relatively easy to detect even if the receiver is not fully synchronized, in terms of symbol timing, with the transmitter. Unfortunately, if timing synchronization with the transmitting station is not accurate, the full energy of a beacon signal may not be detected within a single symbol period. This makes measuring the energy of beacons from different base station transmitters with which timing synchronization may not exist difficult. In order to a mobile to make accurate signal strength estimates, it is important that accurate energy estimation be possible.
In view of the above discussion, it should be appreciated that there is a need for improved beacon signal transmission methods. It would be desirable if improved beacon signaling and/or methods of transmitting and/or using beacon signals were available which would facilitate both accurate energy detection and/or facilitate timing synchronization with the transmitting device, e.g., base station or base station sector transmitter.